1. Field of the Invention
The present invention relates to an organic light emitting display, and more particularly, to an organic light emitting display by which a device characteristic can be improved by varying a thickness of a layer in correspondence with differently colored pixels.
2. Description of the Related Art
An organic light emitting display is a self-luminescent display in which electrons and holes are injected into organic materials from an anode and a cathode and are recombined to generate excitons, and a specific wavelength of light is generated by energy generated from the excitons. Since the organic light emitting display does not require a separate light source such as a backlight unit, it can provide some advantages such as low power consumption, wide angle of view, and fast response speed in comparison with a liquid crystal display device. Therefore, the organic light emitting display has been highlighted as a next generation display.
The light emitting elements of the organic light emitting display include an anode which is an electrode for injecting holes, an organic thin film, and a cathode which is an electrode for injecting electrons. The organic thin film includes organic materials capable of emitting red, green, and blue light to implement a full-color display.
In addition, the organic thin film can have a multi-layer structure that includes an emitting layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) in order to increase light emitting efficiency by balancing the electrons and the positive holes. In some cases, the organic thin film can further include a separate electron injection layer (EIL) and a hole injection layer (HIL). In the organic light emitting display having a multi-layered organic thin film structure, a required optical thickness of the organic thin film is different depending on each pixel that implements a different color. However, what is needed is an improved structure for an organic light emitting display that provides improved color purity while being easy and inexpensive to make.